Magnetic testing device



March 25, 1930. F. H. oHLAND MAGNETIC TESTING DEVICEv Filed Junel'r. 192s INVENTOR -Z'reJH/Lland.

' ATTORNEY Patented Mar. 25, 1 930 l l E. ,7

` UNITEv STATES PATENT oFFifcE Application led June 17, A192:43. Serial No. 116,667.

The invention generally has reference to, In the drawing, in'which like numerals of steel testing devices and primarily has for reference indicate like parts in all of the figits object to provide a mechanical means for ures, l indicates a tube of non-magnetic maascertaining the critical point in the process teri'al, such as brass, fromthe rear end of V5 of tempering steel. which projects a heat non-conducting'han- 55 In the hardening of steel the mass is heated dle 2. Y 'f to gradually increasing temperature up to a The 'tube l is provided with graduations 3 certain desired degree and then suddenly at the upper edge of itsfront end'for a purcooled. Itis diiiicult to ascertain the critical pose later to be described. f

point in this process, that is, the point at Intermediately of its-ends the tube 1 is 50V which the mass should be suddenly cooled provided with across brace l secured in the and it is the purpose of my present invention tube as at 5.

to provide ainechanical means for indicating 1` leaf spring 6 is secured as at 7 to the y this point in the process and supplant theV brace a and projects forwardly therefrom present common method of relying on the centrally'of-the tubel and inaverticalplane. G5

color assumed by the steel when reaching the The spring 6 issecured as at 8 to therear end said critical point. Of a iXed magnet 9,said magnets rear end In its more detail nature, the invention being projected into the'front end of the tube j seeks to provide a simple and eflicient instruand the advance end of said magnet project- :2O ment by the use of which the critical point ing a dstanfe beyond the said tube end. 70

I point. Y

in the process of hardening steel may be eirllhe magnet is provided at its upper edge ciently indicated, the said instrument comadjacent the front end ofthe tube with a prising a non-magnetic support anda vibralpointer 0r indicator linger 10, the said finger tory magnet carried thereby which will be @Xtelldlng over the upper advance edge of 25 caused to vibrate when the instrument is the tube to cooperate with'the graduations 3 75 held within the inuence of the steel being With Which the said tube edge is provided heated and which will cease to vibrate as the vlNhen theparts above" described are in the critical point in the process is reached and IlOIfIhulV POSltlolur the magnet 8, resiliently 4 thus indicate the reaching of said critical IuOunted upon the spring, is at rest with the indicator 10 thereof` directly above theSO With the above and other objects in view Central graduation Vatithe topedge of the that will hereinafter appear the invention tube. j further resides in the novel details of conlu use, the advance lend of the tube 1 is W struction', combination and arrangement of PTOJGCtGd lntO .pOSltoIi for having the mag- 353' parts, all of which will be first fully described, Het Carried,V thereby influenced by the mag- 85 then be particularly pointed out in the apnetic conductivity of thesteel being heated, pended claims, reference being had to the ac the Sald magnet thus being deiiected latercoinpanying drawing, in which: Y ally by reason of the magnetic attraction of Figure 1 is a perspective view of the inventhe same toward the steel body and the resili- 40 tion ent mountingthereof in thesaid tube.' 99' Figure 2 is a centralhorizontal section of It is YVlllI1pWI1-that as the steel reaches the instrument looking upward. the critical point in the heating process it Figure 3 is a cross section taken through lOSGS ull, QI' Substantially all, of its magnetic the front or indicator end of the instrumentx Conductivity, thus, the deflection of the mag Figure 4 is a central longitudinal section net 9 will'continue so long as it is being in- 95 illustrating a modified form of the invention. fluenced by the magnetic conductivity of the Figures 5 and 6 are a side elevation and steel body. withy which itis `being held in end view respectively of a spring support by proximity, Abut upon.y the reaching` of the which the instrument may be supported in critical point, the steel body loses itsgmag-` o use if desired. netic conductivity, the magnet 9 will 'cease u to be influenced thereby and its indicator Will come to rest above the central graduation upon the tube end, thus indicating that the critical point in the heat-ing process has been reached.

In Figure 4 of the drawing, I have illustrated a slight modification in which instead of using 4aiiixed magnet an electromagnet is employed.

In the said Figure 4, 11 indicates the electromagnet core body around Which'is i Wound the coil 12 of insulated Wire, the end of the said Wire being carried out of thetube j 1 and connected With a suitable source of electrical energy, diagrammatically indi-Y thereof, said tubular member having at one end visible graduation lines thereon, an indicator finger carried by the projecting end of said magnet and including a baclvvardly extended portion to overlie said graduated end of said tubular member and cooperate with the graduations thereon to indicate .deflection offsaid ma net when the same is positioned to be ini uenced by a magnetic sub- Staftl'C'lV 'i FRED H. OI-ILAND.

cated at 13, through the make and V break the tube carryinghandle, the `said-block being 3 equipped with a spring clip l16 adapted to partially Vencircle the said handle to secure" the same upon the block. Y

In thev foregoing description I haveV dis closedV a simple yand eliicient instrumentV l whereby the critical point in tempering steel may be eiiiciently andV mechanically indicated, the' said instrument being simple in` construction, economical to manufacture and e'iciently operable for its intended purposes.

lVhat I claim is :v 1. A device ofthe class described comprising a tubular supporting member of nonmagn'e'tic material, a cross Wall secured in one cn'd of the tubular member, ya springV having' one end secured in the lcross W'all-andhaving its free end projected axially rpart Waytof Ward the other end of the tubular member', and ay magnet secured to the free end `of the spring to be suspended freely in-andproject lromthe said other tube end, said cross Wallv being spaced linwardly ofv the'tubularl mem# ber end in which it is mounted'to form an'v end socket, a handle oi? heat non-conductive'ma- 'serial secured in and projecting from the'end socket, graduations" onf-he other tubular member end, and an indicatorpinfterl cairried bythe magnet andassociatedwith'the` graduationsl for the purposes specified;

2. A device of the class' described conpri'sl" ing a, tubularV supporting me'mberfof nonmagnetic. material, a bar'magnet projecting' into andv from' on'e end of lzthe tubular 4-mem-A ber, means jincludlng aflexible *leaf .sp'ringf` for mounting the magnet thetbu-larmember' end te permit vibratoryfmovement* 

